Screw driver for replacing dimmers on table lamps

Hello Friends,
I have two beautiful IKEA lamps and both of them have stopped working. None of my screw drivers are able to open up the dimmers. Can someone tell me what screw driver should I get to do that? Is it the jewellers screwdriver set like this one http://www.alibaba.com/product-gs/54...river_set.html . Anything like this available in USA. Couldn't find anything online?